Cardio Equations

Question 1

Cardiac Output

Answer 1

CO = SV x HR

Question 2

Fick Principle

Answer 2

CO = (rate of O2 consumption) / (arterial O2 - venous O2)

Question 3

MAP

Answer 3

p = QR

MAP = CO x TPR

MAP = (2/3 diastolic P) + (1/3 systolic P)

Question 4

Stroke Volume

Answer 4

SV = EDV - ESV

Question 5

Wall Tension

Answer 5

Tension = pressure X radius

Question 6

Wall Stress

Answer 6

Stress = (pressure X radius) / (2 X wall thickness)

Question 7

Ejection Fraction

Answer 7

EF = SV / (EDV)

Question 8

Resistance

Answer 8

R = P/ Q = Pressure Diff / flow

Resistance = 8 (viscosity) X length / pi r^4

Question 9

Resistance of Vessels in Series v Parallel

Answer 9

Series … Rtotal = R1 + R2 + R3

Parallel … 1/Rtotal = 1/R1 + 1/R2 + 1/R3

Question 10

Starling Equation

Answer 10

Flow (out of vessel) = Kf [(Pc - Pi) - sigma (piC - piI)]

Flow inc if more cap press, higher Kf cap permeability, dec cap oncotic press or inc interstitial oncotic press)